remember that most pet store guppies you buy will come to you already pregnant, so rather than building up a large breed stock, you should give them a few weeks to all have any fry they're going to, and then grow them out, rehome the ones that won't work for you (wrong color, wrong body shape, and get your gender ratios right, about three girls for every boy) and see if you can't develop a good population right off the bat from the cream of the crop.
So remember, when you're feeling very small and insecure,
How amazingly unlikely is your birth,
And pray that there's intelligent life somewhere up in space,
'Cause there's bugger-all down here on Earth.
Loki/Grendel/Gail/Beowulf/Camilla/River/Bathory/Arwen/Lafayette/Deb/Jack Skellington (soon)